(1) Field of the Invention
The invention relates to tobacco treating processes and more particularly to an improved process for expanding and reducing the moisture content of tobacco.
(2) Brief Description of the Prior Art
It is known in the manufacture of smoking articles to expand tobacco utilizing carbon dioxide in both the liquid and pressurized gaseous states or only utilizing carbon dioxide in the pressurized gaseous state, to subsequently reduce the pressure to solidify the carbon dioxide within the tobacco structure, and to heat the tobacco to vaporize the solid carbon dioxide, while simultaneously drying and expanding the tobacco. For example, unexpired U.S. Pat. No. 4,235,250, inventor, Francis V. Utsch, and issued on Nov. 25, 1980 teaches treating tobacco with carbon dioxide gas at 250 psig, cooling the system to a selected carbon dioxide enthalpy, decreasing the pressure on the system and heating the system to expand the tobacco. Further, this patent, like unexpired U.S. Pat. Nos. 4,258,729 and 4,333,483, inventors, Roger Z. de la Burde, Patrick E. Aument and the same Francis V. Utsch, and issued on Mar. 31, 1981, and June 8, 1982 respectively, teach pre-snowing the tobacco with finely divided solid carbon dioxide prior to gaseous carbon dioxide treatment in amounts of 5-50% by weight of tobacco to increase the amount of carbon dioxide retained by the tobacco.
Unexpired U.S. Pat. No. 4,250,898, inventor, Francis V. Utsch et al and issued on Feb. 17, 1981, teaches a similar process to U.S. Pat. No. 4,235,250 of contacting tobacco with gaseous carbon dioxide at at least 50 psig pressure and cooling to solidification of the carbon dioxide.
Unexpired U.S. Pat. No. 4,336,814, inventor, Larry M. Sykes et al and issued on June 29, 1982, teaches impregnating tobacco with liquid carbon dioxide, solidifying the carbon dioxide and vaporizing the same to cause tobacco expansion.
Unexpired U.S. Pat. No. 4,340,073, inventor, Roger Z. de la Burde et al and issued on July 20, 1982, teaches impregnating tobacco with liquid carbon dioxide with the tobacco being maintained at temperatures no lower than about -20.degree. C., solidifying the carbon dioxide and vaporizing the same to cause tobacco expansion.
The prior art practices have resulted in fill value improvement, but often requiring lengthy impregnations, elaborate and expensive equipment and substantial operating costs with concomitant losses in the desired chemical and physical properties of the final tobacco product.
In accordance with the process of the present invention an improved, homogenous tobacco product is obtained having a comparatively high fill value improvement with comparatively substantially equal or sometimes reduced losses of alkaloids and total sugars with the process requiring reduced treating time and reduced operating and material costs. Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein.